March 8, 1894] 



NATURE 



439 



since the year 1812 every year ending with 4 had less than the 

 average rainfall, excepting that every twelfth year reckoning from 

 i860 has had more than the average rain. According to this, the 

 present year should be a dry one. Another diagram repre- 

 sented a notable instance of a torrential rain which occurred in 

 the metropolis on June 23, 1878. It is an unusual thing in 

 London for an inch of rain to fall in twenty-four hours, but in 

 this case 3I inches fell in an hour and a half. 



The U.S. Monthly Weather Review for November contains 

 some remarks by the editor on a series of measurements of the 

 growth of trees, made by Mr. J. Keuchler, of Gillespie County, 

 Texas, about two hundred miles north-west from the Gulf 

 Coast at Indianola. Mr. Keuchler seems to have adopted the 

 idea that a tree bears the history of its climatic surroundings 

 written in itself, and that its annual rings of growth vary in size 

 mainly with the supply of water to the roots, so that broad rings 

 indicate wet years, and thin rings that can scarcely be distin- 

 guished with the naked eye denote dry years. After carefully 

 selecting trees for his measurements, he felled three oaks, two of 

 which were over 130 years old. He cut a perpendicular section 

 from each trunk near the thick end, planed its surface very 

 smooth, and then varnished it over, which made the annual ring 

 distinctly visible. From each section a table was prepared of 

 the relative order and position of the annual rings ; upon com- 

 paring these three tables they were found to correspond 

 exactly, thus indicating that moisture is the principal cause of 

 the difference in the breadth of the rings. Taking the width of 

 the respective rings as a criterion of moisture, the record of 134 

 years shows 6 years extremely dry ; 8 very dry ; 19 dry ; 17 

 average ; 18 wet ; 60 very wet ; 6 extremely wet. The editor 

 of the Review points out that the large number oi very wet years 

 is not at all in accord with the rainfall records during the years 

 1840 to 1890, and, in fact, no region on the globe is known 

 where the distribution of the rainfall is similar to that given by 

 these records. It is evident, therefore, that the breadth of the 

 annual rings of growth adopted by Mr. Keuchler as correspond- 

 ing to dry and average and wet seasons needs considerable 

 modification. The width of the annual rings depend, at least in 

 part, upon the evaporation, the sunshine, the temperature, and the 

 distribution of rain in frequent showers or in frequent heavy 

 floods. It is the combination of several favourable meteor- 

 ological circumstances that must have produced the large num- 

 ber of broad rings which Mr. Keuchler has attributed to 60 very 

 wet years and 6 other extremely wet years. In fact, the editor 

 continues, it is best not to attempt to establish any fine details 

 as to the climate from such a record of tree growth, but to be 

 content with the general statement that there were 14 years 

 during which the climate was unfavourable for the increase of 

 woody fibre, 54 years during which there was an average 

 favourability, and 66 years that produced large growth owing to 

 very favourable conditions. All that can safely be concluded 

 is that during 134 years there were 66 in which the rainfall was 

 well conserved for the use of the tree. 



A PAPER, by Dr. G. Agamennone, on the velocity of propa- 

 gation of the principal earthquakes felt at Zante during 1893, 

 was communicated to the Reale Accademia dei Lincei in 

 December last. The method adopted for the calculation of the 

 velocity was that used by Newcomb and Dutton in the case of 

 the Charlestown earthquake of August 31, 1886. {Amer. jfotir. 

 Sci. vol. XXXV. 1888, p. I.) For the earthquake of January 31, 

 1893, a velocity of 4*040 kilometres per second was obtained, with 

 a probable error of i '120. The earthquake of February i, 1893, 

 appeared to have travelled with an average velocity of 3*280 db 

 0700 kilometres per second, and that of March 20 was propa- 

 gated at the rate of 2'33o ± 0*330 kilometres. In these three 

 cases, Strasburg, at a distance of 1600 kilometres, was the most 

 NO. I 27 I, VOL. 49] 



remote station from Zante at which records of the wave were 

 obtained. The disastrous shock of April 17, 1893, was recorded 

 at Zante at 6h. 30m. 20s., Rome mean time, and it reached Pols- 

 dam, 1730 kilometres distant, at 6h. 41m. 40s. From these 

 times, and those obtained at eight intervening stations, a velocity 

 of 2*340 ± 0*300 kilometres was calculated. The rate of pro- 

 gression of the wave felt on August 4 was 2*120 ± 0*27 kilo- 

 metres per second. Taking all five earthquakes, and including 

 only the observations of the times of maximum phase, a mean 

 velocity of 2*43 ± 0*07 kilometres was obtained. The mean 

 velocity derived from a discussion of the commencement of the 

 disturbances on the seismograph records was 3*085 kilometres ; 

 but whether the difference is due to the higher velocity of the 

 first earth tremors, or merely results from the inability of some 

 of the seismographs to record very small movements, seems to be 

 doubtful. The point is an important one, however, and one to 

 which attention should be directed. 



Since the experiments of Profs. Reinold and Riicker on the 

 thinnest liquid films, the peculiar behaviour of the black areas 

 in soap films has become well known. Herr F. Kohlrausch, in 

 Wiedemamt' s Annalen, describes a method of producing glass 

 films of equally slight thickness, which share the remarkable 

 stability of black liquid films. These are obtained by blowing 

 out one of the duplex capillaries used by the author for mount- 

 ing electrodes. These blow one into spheres with a partition 

 across the centre, which may be reduced to extreme thinness. 

 Those which exhibit Newton's colours of the first and higher 

 orders break very soon, but those which are reduced far enough 

 to appear black are sufficiently stable to keep indefinitely. 

 Any moisture must be pumped out of the sphere, and the 

 openings sealed ap. The black areas are almost indistinguish- 

 able from holes in the plate, but show slight reflection at large 

 angles of incidence. A peculiar phenomenon connected with 

 these spheres is the note they give out daring cooling. This 

 note often lasts half a minute, and is analogous to that of a 

 Trevelyan instrument with the exception that air is substituted 

 for lead. 



The results of the investigations that reached a successful 

 termination during the first year of the existence of the Yale 

 Psychological Laboratory, New Haven, Conn., have just been 

 published under the editorship of Dr. E. W. Scripture. One 

 of the most important of the papers in the volume bears the 

 title " Investigations on Reaction-Time and Attention," and is 

 by Dr. C. B. Bliss. The general results of the experiments 

 are summed up asfoUows : (i) The experiments did not indicate 

 any difference in reaction-time produced by changing the colour 

 of the light present in the field of vision. (2) No difference 

 was detected between the times of reactions in the dark and 

 those made while looking at a stationary incandescent light of 

 six-candle power, (3) When this light was in motion the 

 reaction-time was lengthened. (4) No difference was detected 

 between the times of reactions in silence and those made while 

 listening to the steady sound of a tuning-fork making 250 

 vibrations per second. (5) When the intermittent sound of a 

 metronome was substituted for that of the fork, the reaction- 

 time was lengthened. (6) The reaction-time to a sound heard 

 in both ears is shorter than when the sound is heard only in 

 one ear, even after making allowance for the difference in 

 intensity. 



The ninth annual report of the operations of the U.S. 

 Bureau of Ethnology during the fiscal year 1887-88 has recently 

 been issued. Bound up with the report are two papers, in one of 

 which Mr. John Murdoch describes the ethnological results of 

 the International Polar Expedition to Point Barrow, Alaska ; 

 while the other, by Captain J. G. Bourke, contains a mass of 

 information concerning the medicine-men of the Apache Indians. 

 Mr. Murdoch's paper is a simple and exhaustive account of the 



